On Sat, Sep 04, 2004 at 01:44:28 +0200, David Olofson wrote: > On Saturday 04 September 2004 00.16, Steve Harris wrote: > [...] > > > I *think* bluetooth should be able to handle the bandwith > > > requirements of a mouse (125 Hz frame rate for the MX models, > > > IIRC), but 15-20 ms latency spikes would be an issue that cannot > > > be fully compensated for regardless of bandwidth. Jitter or delay > > > (buffering to eliminate jitter) would cause problems with real > > > time controllers, such as mice or musical controllers. > > > > Bluetooth can do realtime ADPCM audio, so a mouse should be no > > problem. Maybe HID controllers use a different bit of the protocol? > > I dunno... Either way, ADPCM audio is just a matter of bandwidth, but > latency seems to be the issue here. 15-20 ms (in addition to > driver/OS polling latency + jitter and video buffering latency) is > unacceptable for a gaming mouse, so I suspect that messages are just > sent and handled ASAP, without timestamping. Just means you get > terrible jitter instead, which is probably *worse* than the > latency...
There cant be any latency jitter on the audio... I would guess that either that part of the protocol is reserved for audio in some way, or the logitech implementation is just rubbish. - Steve
